list - Implement `[1,2].contains(2)` in JavaScript -

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• how check if array includes object in javascript? 38 answers

essentially require:

if( [1,2].contains(2) ) {...} 

i surprised can't find simple solution this.

is possible add contains method javascript's list type?

underscore's similar functions: _.contains vs. _.some , _.map vs _.each offers:

_.contains([1,2], 2); 

however, _ jquery, , still rather clumsy.

the solution of tushar right, recomend way:

object.defineproperty(array.prototype, 'contains', {     writable: true,     configurable: true,     enumerable: false,     value: function(val) {         return this.indexof(val) !== -1;     } }; 

the reason many libraries depend on construction

for (var in array) ... 

if define function without setting enumerable property false, such cycles eterate through function well. enumerable = false prevents that.